Fuel quantity gauging systems are generally tailored for operation with a specific fuel type. For example, one known fuel quantity gauging system was originally tailored specifically to match JP-4 fuel. Therefore, to be utilized with JP-8 fuels, the fuel quantity gauging system had to be reconfigured. Without reconfiguration, inaccuracies in the amount of fuel reported, via a display or indicator, may result. The inaccuracies are, at least in part, caused by variations in the dielectric constant (K) and the density (D) associated with each specific fuel type. More specifically, variations in the K and the D associated with various fuels affects accuracy of a fuel quantity gauging system. In one example, a fuel quantity gauging system is specified to provide an accuracy of ±1% full scale ±1% quantity of fuel indicated.
New synthetic fuels are becoming available. These synthetic fuels have different physical properties than the JP-4 and JP-8 fuels mentioned above and different physical properties than other currently utilized fuels. A portion of those different physical properties include the dielectric constant, K, and the density, D. Various fuel combinations of JP-4, JP-8, other fuels, and the synthetic fuels are viable for utilization with current jet engines. However, mixtures of such fuels result in differing K and D properties.
As explained above, current fuel quantity gauging systems may be inaccurate for certain fuel mixtures. It is desirable to eliminate such fuel gauging errors, specifically those related to fuel property variations, that are reflected in one or more of fuel tank shut off, fuel center of gravity derivation, total fuel indication, take off gross weight derivation, increase in fuel reserves, extra carried weight, and landing gross weight derivation to increase flight safety.